Flying rotorcraft toy

ABSTRACT

A flying toy having a driven propeller mounted in a duct, with lifting rotor blades extending from the top of the duct, the outer ends of the blades being interconnected by a protective annular ring. The duct and blade assembly rotates in the opposite direction to the propeller, due to torque, the lift of the blades adding to that of the propeller for vertical propulsion. When power is shut off, the toy descends gently in autorotation. The airframe structure is a simple unitary molding and the rotor blades are partially adjustable in pitch to vary the effective lift and thus control the flight.

United States Patent Inventor 2,980,365 4/1961 Yohe 244123 3,394,906 7/1968 Rogers 46/75 X FOREIGN PATENTS 465,032 4/1914 France 244/44 1,347,733 10/1962 France 244/23 OTHER REFERENCES Rose et al., Low-speed Investigation of a Thin, Paired Double-wedge Airfoil Section with Nose Flaps of Various Chords, Feb. 1950, p. 7, 244/42.6

American Modeler, Vol. 52 No. 6, Sept. 1959, p. 28 46/75 Primary Examiner-Russell R. Kinsey Assistant ExaminerJ. A. Oliff AttorneyCarl R. Brown ABSTRACT: A flying toy having a driven propeller mounted in a duct, with lifting rotor blades extending from the top of the duct, the outer ends of the blades being interconnected by a protective annular ring. The duct and blade assembly rotates in the opposite direction to the propeller, due to torque, the lift of the blades adding to that of the propeller for vertical propulsion. When power is shut off, the toy descends gently in autorotation. The airframe structure is a simple unitary molding and the rotor blades are partially adjustable in pitch to vary the efiective lift and thus control the flight.

[72] Leonard E. Mueller 4557 Mt. Hubbard Ave., San Diego, Calif. 92117 [21] Appl. No. 863,953 [22] Filed Oct. 6, 1969 [45] Patented Sept. 7, 1971 [54] FLYING ROTORCRAFT TOY 3 Claims, 3 Drawing Figs.

52 us. Cl 46/74 D, 244/23 C [51] Int. Cl A63h 27/00 [50] Field of Search 46/1 .1, 740, 75, 243 AV; 244/12 C, 23 C, 17.23, 17.25, 42.4, 42.6, 44

[56] References Cited UNITED STATES PATENTS D.209,763 1/1968 Mueller 46/75 UX 1,190,378 7/1916 Clark.... 244/44 1,684,567 9/1928 Wragg. 244/42.4 X 2,169,325 8/1939 Novak 244/42.4 X 2,949,693 8/1960 McRoskey 46/75 IO I6 PATENTED SEP 7 Ian nOOOOOn/ofzo INVENTOR. LEONARD E. MUELLER {Ma @MW ATTORNEY FLYING ROTORCRAFT TOY BACKGROUND OF THE INVENTION Rotary type flying vehicles usually have some form of propeller or fan propulsion for vertical lift, an airframe being suspended from the propulsion means and stabilized in a suitable manner. Unless counter rotating propellers or fans are used, some antitorque means is used to prevent the air frame from rotating. This leads to complications which may be unnecessary, particularly in a toy.

SUMMARY OF THE INVENTION The flying toy described herein has an engine mounted in a duct and driving an axially thrusting propeller. At the top of the duct are outwardly extending rotor blades, joined at their outer ends by a protective annular ring. The rotor blades have portions which are adjustable to vary the effective pitch and thus control the lift. With the engine in operation, the propeller rotates in one direction and the entire airframe rotates in the other direction, due to torque, the lift of the rotor blades adding to the lifting thrust of the propeller. In unpowered flight, the unit autorotates to a gentle landing.

It is therefore an object of this invention to provide a new and improved flying rotorcraft toy.

Other objects and many advantages of this invention will become more apparent upon a reading of the following detailed description and an examination of the drawing wherein like reference numerals designate like parts throughout and in which:

FIG. 1 is a top plan view of the complete rotorcraft.

FIG. 2 is a sectional view taken on line 2-2 of FIG. 1.

FIG. 3 is an enlarged sectional view taken on line 33 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The rotorcraft can be assembled from parts but is preferably in the form of a unitary frame which is easily molded or otherwise made from plastic material. The structure comprises a generally cylindrical duct having an outwardly rolled upper rim 12, from which a plurality of rotor blades 14 extend sub stantially radially. Four blades are shown as an example, but other arrangements could be used. Blades 14 are inclined downwardly from the top of duct 10 and their outer ends are interconnected by an annular tip ring 16, the blades and ring being in a substantially conical configuration. Each rotor blade 14 is curved in cross section with a concave underside 18, and has a leading edge portion extending forward in the direction of rotation. The leading edge portion is separated from the rim I2 and tip ring 16 by notches 22 and 24, and is provided with a row of spanwise perforations 26 which facilitate bending of the leading edge, as hereinafter described.

At the lower end of duct 10 are radially inwardly extending arms 28 supporting a central platform 30, on which an engine 32 is mounted with its drive shaft 34 vertical. The engine is a conventional glow plug ignition type as used in model aircraft, and various types and sizes are readily available. The downwardly thrusting propeller 36 need not be a particularly close fit within the duct, since the power to weight ratio of the craft is high. counterclockwise rotation is standard with such engines, so rotor blades 14 are arranged for clockwise rotation.

To operate the rotorcraft the engine is started in the conventional manner and adjusted for maximum power. The craft is launched in a generally horizontal motion, preferably with a clockwise rotating motion for assistance. Propeller thus will sustain the craft and torque will increase the rotation speed of the frame, the combined lift of the propeller and rotor blades causing the craft to rise. The rotation gives the craft considerable gyroscopic stability and there is no tendency to pitch over or oscillate violently. The rate of climb is controlled by adjusting the leading edge portions 20, as shown in FIG. 3. By

bending the leading edges up, as in one broken line position 20a, the effective pitch angle of the blade 14 is increased and the craft will climb rapidly. Bending the leading edge down, as in the other broken line position 20b, the blade pitch is effectively decreased and climb is minimized, the craft tending to fly nearly horizontally. All the blades should be adjusted as nearly as possible to the same position, but the settings are not critical.

When the fuel is exhausted and the engine stops, the craft will autorotate to a gentle landing. While a rotor usually reverses its direction of rotation to autorotate when power is shut off, it has been found that the inertia and flywheel action of the craft tend to maintain the rotation in the driven direction for some time, resulting in a prolonged flight.

When made from suitable plastic material, the frame will withstand considerable rough usage and the leading edge portions can be bent many times without breakage. The tip ring 16 provides gripping means for launching, strengthens the blades and protects the users hands from the blades when the craft is rotating.

Having described my invention, I now claim.

1. A flying rotorcraft, comprising,

a substantially cylindrical duct having an outwardly rolled upper rim,

a plurality of substantially radial rotor blades extending outwardly and angularly downwardly from said rim,

a tip ring interconnecting the outer ends of said blades, said tip ring, blades and rim being in a conical configuration coaxial with said duct, arms extending across the lower end of said duct and having a platform thereon, and an engine secured on said platform, with a driven propeller thereon mounted for axial rotation is said duct. 2. A rotorcraft according to claim 1, wherein each of said rotor blades has a spanwise row of perforations, for providing a bendable leading edge portion thereof.

3. A rotorcraft according to claim 2, wherein said duct, said arms, said rotor blades and said tip ring are made from a single piece of material. 

1. A flying rotorcraft, comprising, a substantially cylindrical duct having an outwardly rolled upper rim, a plurality of substantially radial rotor blades extending outwardly and angularly downwardly from said rim, a tip ring interconnecting the outer ends of said blades, said tip ring, blades and rim being in a conical configuration coaxial with said duct, arms extending across the lower end of said duct and having a platform thereon, and an engine secured on said platform, with a driven propeller thereon mounted for axial rotation is said duct.
 2. A rotorcraft according to claim 1, wherein each of said rotor blades has a spanwise row of perforations, for providing a bendable leading edge portion thereof.
 3. A rotorcraft according to claim 2, wherein said duct, said arms, said rotor blades and said tip ring are made from a single piece of material. 